Obstructive sleep aponea

Question 1

Deina OSA?

Answer 1

Recurrant episodes of partial or complete upper (pharyngeal) airway obstruction during sleep, intermittent hypoxia and sleep fragmentation.

Question 2

What is OSA syndrome?

Answer 2

When OSA manifests as excessive daytime sleepiness.

Question 3

Describe the mechanisms of OSA?

Answer 3

Pharyngeal narrowing > negative thoracic pressure > arousal > sleep disruption (causeing reduced QOL due to lseepiness and increased risk of RTAs) / BP surge (increasing risk of MI and stroke).

Question 4

Who normally presents with OSA?

Answer 4

Men aged 40-50.

Increased incidence with obesity.

Question 5

What are the symptoms of OSA?

Answer 5

• loud snoring
• restless sleep
• choking
• dry mouth
• sweating
• fatigue/low mood/reduced concentration
• unrefreshed sleep
• deytime solnolence

Question 6

Describe assessment of someone who presents with OSA?

Answer 6

• History: from patient and partner.
• Clinical exam: weight, BMI, neck circumference (>40cm bad), craniofacial apearance (e.g. retronathia, micrognathia), tonsils (big?), nasal patency.
• Use Epworth Sleepiness Score to assess for OSA.

Question 7

What investigations could be done to assess if someone has OSA?

Answer 7

1. Limited Polysomnography
   - 5 channel home study
   - Measuers O2 sats, HR, flow of air, body position and thoracic and abdominal effort.
2. Full Polysomnography
   - EEG for sleep staging
   - video and audio
   - thoracic and abdominal effort
   - position
   - air flow
   - O2 sats
   - limb leads for limb position
   - snoring
3. Transcutaneous O2 sats and CO2 assessment (TOSCA)
   - can be done at home or as inpatient.

Question 8

What are the advantages of a full polysomnography?

Answer 8

• Ensure its the correct patient
• accurate assessment of sleep efficacy (are they getting enough sleep?)
• Sleep staging via EEG
• Can see any parasomnic activity

Question 9

Define aponea?

Answer 9

The cessation or near cessation of air flow.

4% O2 desaturation lasting 10+ seconds.

Question 10

Define hypoaponea?

Answer 10

Reduction of airflow but not significant enough to be an aponea.

Question 11

What is a respiratory efort related arousal?

Answer 11

Arousal associated with a change in airflow that doesn’t meet criteria of hypoaponea or aponea.

Question 12

How dd you calculate the aponea-hypopnoea index?

Answer 12

Add the number of aponeoas and hypoapopnoeas and divide by the total sleep time in hours.

Question 13

What is the oxygen desaturation index?

Answer 13

Number of times per hour of sleep the SpO2 falls >4% from baseline.

Question 14

What aponeo-hypopnoea index diagnostic of OSA?

Answer 14

• AHI: >15

- AHI 5-15 with compatible symptoms

Question 15

How is severity in OSA categoriesed?

Answer 15

AHI 5-15: mild
AHI 16-30: moderate
AHI >30: severe

Question 16

What patients with OSA do we treat?

Answer 16

Only treat the symptomatic e.g. those with daytime sleepiness.
Aim to improve sleepiness and QOL

Question 17

Describe management of OSA?

Answer 17

• Advise on weight loss
• Avoid trigger factors e.g. alcohol
• Treat underlying conditions e.g. large tonsils, hypothyroidism, nasal obstruction.
• Continuous positive airway pressure (CPAP): mask over nose directs air to the throat to keep airway open.
• Mandibular advancement devices: Mouthguard which pulls jaw forward.
• Maxillofacial surgery: those with anatomical problems which are severe.
• Sleep position trainers: For those with supine OSA, device that vibrates when you lie on back.

Question 18

What are the complications of untreated OSA?

Answer 18

• hypertension
• right heart strain
• CV disease
• increase risk of CVA
• increased accidents/poor concentration

Question 19

How likely are patients with OSA to have an RTA compared to normal?

Answer 19

4x

Question 20

Do patients with OSAS need to form DVLA?

Answer 20

Yes - but can drive if compliant with treatment.